Sort medals ranking by diamonds #680

Clicking the emoji in the column headers on /medals should set the sort column (we could sort by silvers and bronzes, too, for kicks):

The old https://code.golf/rankings/medals/all/all/all should redirect to https://code.golf/rankings/medals/all/all/all/gold, and https://code.golf/rankings/medals/all/all/all/{diamond,silver,bronze} can be the new sorted pages.